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United States Patent |
6,048,033
|
Sakurai
,   et al.
|
April 11, 2000
|
Seat back frame
Abstract
There is provided a seat back frame in which the same frame can be used for
both of single reclining and double reclining, and the deformation of side
frame can be controlled against a backward load. The seat back frame is
composed of bilaterally symmetrical side frames, an upper pipe welded to
both upper end portions of the side frames, and a lower pipe welded to the
lower portions of the side frames. The side frames have a wider-in-front
shape such that the width is greater on the front side than on the rear
side. On the face of the side frame, triangular planes are provided so as
to be vertically adjacent to each other, and the common side of the
adjacent triangles is bent.
Inventors:
|
Sakurai; Akihiro (Hamamatsu, JP);
Mizoo; Akihiko (Hamamatsu, JP);
Mizuno; Ryozo (Hamamatsu, JP)
|
Assignee:
|
Suzuki Motor Corporation (Hamamatsu, JP)
|
Appl. No.:
|
010336 |
Filed:
|
January 21, 1998 |
Foreign Application Priority Data
Current U.S. Class: |
297/452.18; 297/361.1 |
Intern'l Class: |
A47C 007/02; B60N 002/02 |
Field of Search: |
297/452.18,361.1,410,452.52,463.2
|
References Cited
U.S. Patent Documents
3971587 | Jul., 1976 | Curtis et al.
| |
4544204 | Oct., 1985 | Schmale.
| |
5044693 | Sep., 1991 | Yokota.
| |
5123706 | Jun., 1992 | Granzow et al.
| |
5328248 | Jul., 1994 | Nishiyama.
| |
5697670 | Dec., 1997 | Husted et al.
| |
Foreign Patent Documents |
57-1807 | Jan., 1982 | JP.
| |
58-15542 | Jan., 1983 | JP.
| |
62-44693 | Nov., 1987 | JP.
| |
2-3328 | Jan., 1990 | JP.
| |
5-37807 | Sep., 1993 | JP.
| |
2510289 | Jun., 1996 | JP.
| |
Primary Examiner: Nelson, Jr.; Milton
Attorney, Agent or Firm: Alston & Bird LLP
Claims
What is claimed is:
1. A seat back frame for a seat back of an automotive seat, comprising:
right and left side frames each including a reclining installation portion
adapted for attaching a reclining device to the respective side frame;
an upper frame connecting the upper ends of said right and left side
frames; and
a lower frame connecting the lower ends of said right and left side frames;
each of said right and left side frames having a face which includes at
least two triangular planes, each of the triangular planes having two
sides which extend from one edge of the respective side frame face to the
other edge thereof and the remaining side of each triangular plane forming
a portion of one of the edges of the respective side frame face, the
triangular planes of each side frame face being vertically adjacent and
joined at boundary lines therebetween and angled with respect to each
other so as to form a bent plane on each side frame face, whereby a
backward load applied to the seat back causes the side frames to deform at
the bent planes along the boundary lines between the contiguous triangular
planes of each bent plane.
2. A seat back frame according to claim 1, wherein each of said bent planes
is formed by three triangular planes having two boundary lines
therebetween, and the bending of each said bent plane is in one direction
about one of the boundary lines and in an opposite direction about the
other boundary line.
3. A seat back frame according to claim 1, wherein the lower frame is
connected to each side frame at a location between the bent plane and the
reclining installation portion of the respective side frame.
4. A seat back frame according to claim 3 wherein each side frame includes
a step portion which protrudes inwardly, the lower frame being attached to
each side frame at the respective step portion thereof.
5. A seat back frame according to claim 1, wherein the transverse distance
between front sides of said right and left side frames is greater than the
transverse distance between rear sides of said right and left side frames,
whereby the seat back frame is adapted to accommodate a seat back that is
wider at its front face than at its rear face.
6. A seat back frame according to claim 1, wherein each of said right and
left side frames includes a curved portion having a shape complementary to
the shape of the outer contour of the upper frame for attaching the upper
frame to said right and left side frames.
7. A seat back frame for a seat back of an automotive seat, comprising:
right and left side frames each including a reclining installation portion
adapted for attaching a reclining device to the respective side frame, the
side frames being arranged such that the seat back frame is wider at a
front side thereof than at a rear side thereof, each side frame including
an L-shaped hook attached to a side of the respective side frame;
an upper frame connecting the upper ends of said right and left side
frames;
a lower frame connecting the lower ends of said right and left side frames;
a reclining device fitted to the reclining installation portion of one of
the right and left side frames;
the reclining installation portion of the other side frame comprising a
free hinge portion;
each of the side frames including a curved portion having a shape that is
complementary to the outer contour of the upper frame, each of the side
frames having a face which includes at least two triangular planes, each
of the triangular planes having two sides which extend from one edge of
the respective side frame face to the other edge thereof and the remaining
side of each triangular plane forming a portion of one of the edges of the
respective side frame face, the triangular planes of each side frame face
being vertically adjacent and contiguous and angled with respect to each
other so as to form a bent plane on each side frame face.
Description
FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an automotive seat and, more particularly,
to a construction of a seat back frame.
To tilt back a seat back for an automotive seat, a reclining device is
provided at the side of a connecting portion between a seat and its seat
back. The reclining device is available in two types: a double reclining
system in which the reclining devices are provided on both sides of the
seat and a single reclining system in which the reclining device is
provided only on one side of the seat.
Therefore, the frame shape of seat backs differs between the double
reclining system and the single reclining system depending on whether or
not the reclining device installation portions are present on the opposite
sides of the seat. More specifically, the double reclining seat back frame
has basically the same shape on the right and left sides because the
reclining device installation portions are present on both sides. As shown
in FIG. 16, for the single reclining seat back frame 31, one side frame is
provided with a reclining device installation bracket 32, and the other
side frame 33 is merely provided with a free hinge hole 34 at the end
thereof. In FIG. 16, reference numeral 33a denotes a retainer welded to
the side frame 33, and 33b denotes a hook provided on the installation
bracket 32.
FIG. 17 shows a side frame 36 for a double reclining seat back frame. As
shown in the figure, the side frame 36 is provided with a bead 39 for
absorbing a load at an arbitrary place between an installation hole 37 for
the reclining device installation bracket and a lower pipe 38. For
example, when an external force is applied to a passenger sitting on the
seat and thereby a backward load is applied to the seat back frame, the
frame is deformed plastically at the portion of the bead 39, whereby the
load applied to the reclining device is controlled.
Also, for the side frame 36 shown in FIG. 17, when an upper pipe 40 is
fixed as shown in FIG. 18, the hatched portion shown in FIG. 17 is
sometimes cut to adjust the height of seat back frame. In such a case, in
order to fix the upper pipe 40 to the side frame 36, the upper end shape
of the side frame 36 must coincide with the outer periphery of the upper
pipe 40. For this purpose, the upper end portion of the side frame 36 must
have the same shape for a certain length.
As described above, since the shape of seat back frame differs between the
double reclining system and the single reclining system, the seat back
frames of two systems must be manufactured separately, resulting in poor
production efficiency.
As described above, the double reclining seat back frame is provided with a
bead on the right and left side frames to absorb load energy by the
plastic deformation of side frames at the bead portion.
However, although the side frame is deformed under a predetermined load,
the time for which the deformation of the side frame can be controlled is
very short because the side frame is bent at the small bead portion. Also,
because the frame faces of the right and left side frames are parallel to
the longitudinal direction of vehicle body, when the bead is crushed and
then the deformation of frame further proceeds, there is no knowing to
which direction of right and left the side frame falls, and the strength
balance of side frame and upper pipe is destroyed, so that the upper pipe
is sometimes deformed. Because the portion at which the bead is formed
lies between the lower pipe and the installation hole for reclining
device, if a frame torsion occurs after the bead is crushed, there is a
possibility that the reclining device is deformed.
For the single reclining seat back frame, the same bead cannot be formed on
the right and left side frames because the shapes of the right and left
side frames are different. Moreover, since the side on which the reclining
device installation bracket is provided has a high strength, the side
frame on the free hinge side is sometimes distorted when a backward load
is applied to the seat back frame.
OBJECT AND SUMMARY OF THE INVENTION
The object of the present invention is to solve the above problems, and
accordingly an object thereof is to provide a seat back frame in which the
same frame can be used for both of single reclining and double reclining,
the right and left side frames have the equal strength, and the
deformation of side frame can be controlled.
To achieve the above object, a first aspect of the present invention
provides a seat back frame in which a reclining installation portion is
provided on right and left side frames of a seat back for an automotive
seat and an upper frame connecting the upper ends of the right and left
side frames and a lower frame connecting the lower ends thereof are
provided, characterized in that a reclining device is fitted at only one
of the reclining installation portions on the right and left side frames,
and the other reclining installation portion thereof is fitted with a free
hinge metal with which a single reclining seat is supported by a frame for
double reclining seat.
Also, a second aspect of the present invention provides a seat back frame
in which a reclining installation portion is provided on right and left
side frames of a seat back for an automotive seat and an upper frame
connecting the upper ends of the right and left side frames and a lower
frame connecting the lower ends thereof are provided, characterized in
that a face of each of the respective right and left side frames include a
portion defined by at least two triangular planes each of the triangular
planes in which two sides of extend from one edge of the side frame face
to the other edge thereof and the remaining one side forms a portion of
one of the edge of the respective side frame face, and a bent plane is
formed by combining the triangular planes so as to be vertically adjacent
to each other and joined at a boundary line therebetween, by which the
right and left side frames are deformed at the boundary line of the
triangular planes by a backward load applied to the seat back.
Also, a third aspect of the present invention provides a seat back frame in
which a reclining installation portion is provided on right and left side
frames of a seat back for an automotive seat and an upper frame connecting
the upper ends of the right and left side frames and a lower frame
connecting the lower ends thereof are provided, characterized in that a
reclining device is fitted to only one of the reclining installation
portions on the right and left side frames, and the other reclining
installation portion thereof comprises a free hinge portion, the right and
left side frames are shaped so as to be wider in front, a face of each
side frame include a portion defined by at least two triangular planes in
which two sides of each of the triangular planes from one edge extend of
the side frame face to the other edge thereof and the remaining one side,
and change "face is" to face of the side frame face is, a bent plane is
formed by combining the triangular planes so as to be vertically adjacent
to each other, the bending of the bent plane is alternate, the ends of the
lower frame are fixed to the right and left side frames at a position
between the triangular planes and the reclining installation portion, the
respective right and left side frames are provided with a curved portion
with the same shape as or a shape complementary that of the outer
periphery of the upper frame fixed to the upper portions; of the right and
left side frames, and an L-shaped hook is provided at the side of the
respective right and left side frames.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a seat back frame in accordance with an
embodiment of the present invention;
FIG. 2 is a side view of a seat back frame in accordance with an embodiment
of the present invention;
FIG. 3 is a sectional view taken along the line X--X of FIG. 1;
FIG. 4 is a schematic back view of a side frame for a seat back frame in
accordance with an embodiment of the present invention;
FIG. 5 is an enlarged sectional view showing a fixing portion of a side
frame and a lower pipe for a seat back frame in accordance with an
embodiment of the present invention;
FIG. 6 is a perspective view of a side frame for a seat back frame in
accordance with an embodiment of the present invention;
FIG. 7 is a perspective view for illustrating a construction of side frame
upper end portion for a seat back frame in accordance with an embodiment
of the present invention;
FIG. 8 is an enlarged sectional view showing a fixing portion of a side
frame and an upper pipe for a seat back frame in accordance with an
embodiment of the present invention;
FIG. 9 is a perspective view showing a deformed state when a torsional load
is applied to a seat back frame in accordance with an embodiment of the
present invention;
FIG. 10 is a perspective view showing a fixing portion of a hook formed on
a side frame and an S spring for a seat back frame in accordance with an
embodiment of the present invention;
FIG. 11 is a perspective view showing a fixing portion of a hook formed on
a side frame and a full mold wire for a seat back frame in accordance with
an embodiment of the present invention;
FIG. 12 is a perspective view showing a fixing portion of a hook formed on
a side frame and a contour mat for a seat back frame in accordance with an
embodiment of the present invention;
FIG. 13 is a perspective view showing a fixing portion of a hook formed on
a side frame and a coil spring for contour mat for a seat back frame in
accordance with an embodiment of the present invention;
FIG. 14 is a perspective view showing a seat using a seat back frame in
accordance with an embodiment of the present invention;
FIG. 15 is a sectional view taken along the line Y--Y of FIG. 14;
FIG. 16 is a perspective view of a conventional seat back frame;
FIG. 17 is a perspective view of a side frame for a conventional seat back
frame; and
FIG. 18 is a sectional view showing a fixing portion of a side frame and an
upper pipe for a conventional seat back frame.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A seat back frame in accordance with an embodiment of the present invention
will be described with reference to the accompanying drawings.
FIGS. 1 and 2 show a seat back frame 1 in accordance with the present
invention. This seat back frame 1 is mainly composed of bilaterally
symmetrical side frames 2a and 2b, an upper pipe 3 formed as a U-shaped
upper frame welded to both upper end portions of the side frames 2a and
2b, a lower pipe 4 formed as a lower frame welded to the lower portions of
the side frames 2a and 2b, and a back plate 5 welded at the lower part of
the upper pipe 3.
The side frame 2a, 2b is formed of a plate of a U shape in cross section.
As shown in FIG. 2, a line connecting AB to BC at a height positioned at
the lap of a passenger is formed curvedly, and two reclining device
installation bolt holes 7a are formed at the lower end portion. The
reclining device R is provided along the side frame 2a, 2b. A conventional
type of reclining device can be used, so that the explanation of
construction thereof is omitted. As shown in FIG. 3, the side frames 2a
and 2b are shaped wider in front so that the front side 12a is wider than
the rear side 12b. That is, the trasverse distance between side frames 2a
and 2b is greater at the front side 12a than at the rear side 12b. As
shown in FIG. 2, the face of the side frame 2a, 2b is provided with
triangular planes indicated by triangles ADB, BCD, and CDE adjoining in
the vertical direction of the side frame 2a, 2b. Each of these triangular
planes has two sides using two out of the sides a to d extending from the
front side 12a to the rear side 12b of the side frame 2a, 2b and one side
on the front side or rear side of the side frame 2a, 2b.
These triangular planes do not lie on the same plane. As shown in FIG. 4, a
great bent portion is formed on the common side b of the triangles ADB and
BCD, and a bent portion is formed on the common side c of the triangles
CBD and CDE. Also, bent portions are formed on the side a of the triangle
ADB and on the side d of the triangle CDE.
As shown in FIGS. 2 and 3, the side frames 2a and 2b are formed integrally
with three sets of L-shaped hooks 6. These hooks 6 are formed at the same
intervals vertically with the same width, and a retaining hole 6b is
formed in an attaching piece 6a. As shown in FIG. 5, at the lower part of
the side frame 2a, 2b is provided a circular step portion 7b, to which the
lower pipe 4 is welded on the outer side. As shown in FIG. 2, the step
portion 7b is located between the reclining device installation bolt holes
7a and the side d of the triangle CDE. As shown in FIG. 5, the end of the
lower pipe 4 slightly protrudes from the step portion 7b, but does not
protrude from the reclining device installation planes 12.
The reclining device installation planes 12 at the lower parts of the side
frames 2a and 2b are not arranged so as to be wider in front but in
parallel to each other as shown in FIGS. 1 and 5.
As shown in FIG. 6, the end portions of the upper pipe 3 are welded to the
upper end portions of the side frames 2a and 2b. At this fixing portion,
as shown in FIGS. 7 and 8, a recess 8a is formed at the upper part of the
side frame 2a, 2b, a vertically long, curved joint portion 8b is provided
at rear of the recess 8a, and a non-joint portion 8c is provided at the
front. The diameter of the joint portion 8b is equal to the outside
diameter of the upper pipe 3. For the non-joint portion 8c, the width g at
the lower part is larger than the width f at the upper end.
As shown in FIG. 1, a pair of headrest attachment pieces 10 are provided at
the upper part of the upper pipe 3, and a back plate 5 is welded to both
the lower end portions of the upper pipe 3.
The following is a description of the operation and effects of the seat
back frame.
In this embodiment, since both of the side frames 2a and 2b of the seat
back frame 1 can be fitted with a reclining device, this seat back frame
can be used for a double reclining seat. Also, by installing a reclining
device to only one side of the seat back frame 1 and by making the other
side a free hinge, the seat back frame can be used as a single reclining
seat. Thereupon, the same seat back frame 1 can be used for both of single
reclining seat and double reclining seat. Therefore, the seat back frame
of the same shape can be produced in large quantities, resulting in a
decrease in production cost.
Since a great bend portion is formed by the triangular planes ABD and BCD
as shown in FIG. 2 and the side frames 2a and 2b are arranged so as to be
wider in front, the bent portion and tilting direction of the side frame
can be restricted when a backward load is applied to the seat back frame
1.
That is, when the side frame 2a, 2b is bent, the triangular planes ABD,
BCD, and CDE are bent on the common sides b and c, and the areas of the
triangular planes ABD, BCD, and CDE are large. Therefore, the range of
time for which the load input can be controlled is widened, a heavy load
can be received for a long time, and no sudden moment change occurs during
deformation.
In FIG. 6, the direction in which the side frame 2a, 2b is bent is
indicated by arrows. As shown in the figure, the side frame 2a, 2b is bent
in the arrow-marked direction on the sides a, c, and d of the triangles,
and the side b is bent to the inner side of the side frame 2a, 2b.
Therefore, the seat back frame 1 is deformed backward. By this load
control, the upper pipe 3 and the side frame 2a, 2b are balanced in terms
of strength, so that the torsion of the upper pipe 3 can be decreased.
Thus, when the side frame 2a, 2b is deformed by a load, the deformation
takes place at the upper part above the side d of the triangular plane
CDE. Therefore, on the reclining device installation plane 12, a
deformation does not occur, so that the reclining device is not affected
by the load.
FIG. 9 shows a deformed state of the seat back frame 1 in which the side
frame 2a is the free hinge side and the side frame 2b is fitted with a
reclining device so as to be used for a single reclining seat. As shown in
the figure, when the side frame 2b on the reclining device installation
side is subjected to a torsion indicated by arrow by a load such that the
free hinge side of the side frame 2a is twisted, the deformation of the
side frame 2b is started by the bending of the side a of the side frame
2b. In this case as well, the deformation takes place at the portion above
the side d, so that the influence of torsion on the free hinge side is
less liable to be transmitted to the reclining device installation plane
12.
In the case where the seat back height is adjusted when the upper pipe 3 is
installed to the side frames 2a and 2b of the seat back frame 1, the upper
end portions of the side frames 2a and 2b are cut. In such a case, since a
vertically long joint portion, 8b is provided as shown in FIG. 7, the
width f at the upper end and the width g at the lower part need not be a
fixed width. Therefore, the degree of freedom in designing increases, and
also the strength can be increased.
FIGS. 10 to 13 show the hook 6 of the side frame 2b. As shown in FIG. 10,
by forming the hook 6 integrally, the hook 6 can be used as a hook for an
S spring 14. When the seat back frame is used for a single reclining seat,
the need for a conventional retainer, which is installed subsequently, is
eliminated. The hook 6 is fixed by further crimping in the arrow-marked
direction from the state shown in FIG. 10.
Also, as shown in FIG. 11, by forming the attaching piece 6a slightly
larger for the S spring, a thick full mold wire 15 can be attached in the
same frame at a portion where a weld 16 portion does not affect the frame
strength. Besides, as shown in FIG. 12, a mat 17 can also be attached by
crimping the attaching piece 6a. Also, since the attaching piece 6a is
formed with the retaining hole 6b, a coil spring 18 for mat can be
attached.
As shown in FIG. 14, when a passenger sits on a rear seat on a two-door
car, he/she enters the cabin through an entrance 20 at the side of a front
seat 19 by tilting a seat back 21 forward.
In this embodiment, as shown in FIG. 1, the side frames 2a and 2b are
arranged so that the front side 12a is wider and the rear side 12b is
narrower than the reclining device installation plane 12 of the seat back
frame 1. Therefore, as shown in FIG. 15, a corner portion 21a indicated by
a broken line at the rear side portion of the seat back 21 is eliminated,
so that the passenger can get on and off the car easily.
Also, if the side frame planes of the automotive seat back frame are in
parallel in the longitudinal direction of the vehicle body and the seat
width is narrow, the passenger's body comes close to the front side of the
side frame, so that the passenger has a feeling of physical disorder.
Since the side frames 2a and 2b are arranged so as to be wider in front as
shown in FIG. 15, the shape of seat back urethane mounted to the side
frames 2a and 2b is fitted to this form, providing a shape along the back
of human body. When the passenger sits on the seat, the seat back urethane
fits to the human body, by which the riding quality can be upgraded.
Since as shown in FIG. 2, the seat back frame 1 is curved by curving the
line of AB-BC on the rear side of the side frame 2a, 2b, the leg room for
the passenger sitting on the rear seat can be enlarged. The curved shape
of the seat back frame 1 serves as if a side support wire is attached even
if a side support wire is not disposed in the seat back 21.
As shown in FIG. 5, the step portion 7b is provided on the installation
plane 12 of the side frame 2a, 2b, and welding is done so that the welding
portion of the lower pipe 4 and the side frame 2a, 2b is drawn in.
Thereby, the plane rigidity around the welding portion 4a of the lower
pipe 4 is increased, and the crushing of the lower pipe 4 when a load is
applied is relaxed.
The above is a description of one embodiment of the present invention.
Needless to say, the present invention is not limited to this embodiment,
and various modifications can be made on the basis of the technical
concept of the present invention.
As described above, according to the first aspect of the present invention,
the same seat back frame can be used for both of single reclining and
double reclining. Therefore, the same seat back frame can be produced in
large quantities, resulting in a decrease in production cost.
Also, according to the second aspect of the present invention, since the
bent portion is formed on the triangular plane, the bent portion and
tilting direction of the side frame can be restricted when a backward load
is applied to the seat back frame. Also, the range of time for which the
load input can be controlled is widened, a heavy load can be received for
a long time, and no sudden moment change occurs during deformation.
Further, according to the third aspect of the present invention, both the
effects of the first and second means can be achieved.
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